Treatment of clays



Unimd S s Patent TREATMENT OF CLAYS William E. Brown, Gibsonia, andClilford R. Giacobine,

, Oakmont, Pa., assignors to Gulf Research & Development Company,Pittsburgh, Pa, a corporation of Delaware No Drawing. ApplicationNovember 18, 1954, Serial No. 469,857

13 Claims. Cl. 252-855) This invention relates to a process of treatingbodies comprised wholly or in part of clays, including clay-likematerials, for the purpose of maintaining and/ or restoring thepermeability to fluids of such bodies and rendering them stable towarddisruption by mechanical and/ or chemical forces. More particularly,this invention relates to a process of treating bodies comprised whollyor in part of clays, including clay-like materials, subject to swellingand/or dispersion, with subsequent loss of permeability and reduction inmechanical strength, for the purpose of maintaining and/ or restoringthe permeability to fluids of such bodies and rendering them stabletoward disruption by mechanical and/ or chemical forces.

Clay-containing bodies often are substantially impermeable or have a lowpermeability to fluids or lose some or all of the permeability they maypossess when I they are subjected to the action of liquids such aswater, certain brines, emulsions containing water or certain brines,etc. Treatment of such clay bodies in accordance with the process ofthis invention Will render them permeable, prevent a reduction in fluidpermeability and/ or restore fluid permeability to those clay bodies inwhich it has been lost. As a result of the treatment the resistance ofthe clay bodies to mechanical and/or chemical disintegration will alsobe substantially increased.

The clay or clay-like materials which can be treated in accordance withour invention can include any natural geologic formations or artificialformations such as railroad or highway embankments, road beds and roadsurfaces, automobile parking areas, areas for outdoor sports, storageareas, military installations, etc. Included also among the materialswhich can be treated to im prove or maintain their permeability andtheir physical and/ or chemical stability are manufactured articlescontaining clays or clay-like materials. As an example, but withoutbeing limited thereto, this process can be employed to treat articlescast, extruded or otherwise formed from clay to increase theirmechanical strength prior to and/or afterfiring.

The process of this invention has particular applicability in thetreatment of natural geologic formations for the purpose of preventingor correcting the loss in permeability thereof caused by swelling and/ordispersing of the clay contained therein, preserving the approximategeometry of the grains of the formation, maintaining the poredistribution of the formation and firming the formation if it isuncemented or poorly cemented. More specifically, this invention isespecially advantageous in the treatment of a clay-containing formationadjacent a borehole in wells in order to increase, maintain and/orrestore the permeability of the formation by rendering the claycontained therein resistant to swelling, disruption and/or migration,and also to shrink essentially irreversibly the hydrated, swollen claywhich may be present in said formations adjacent wells producing fluids,such as hydrocarbons, Water, etc., or in wells which are used to injectsuch fluids into a geologic with aqueous liquids such as water, certainbrines, emulsions containing water or certain brines, etc. This liquidcan be introduced into the formation as drilling mud filtrate, injectionwater, water from leaks in or behind the casing, or ground waterassociated with the formation. Of particular concern in the case ofintroduced clay is that clay which, as a component of the drilling mud,invades the formation during the drilling of the borehole. High swellingmontmorillonite is often used in drilling muds, among other reasons,because of its ability to create a low permeability filter cake on theformation. Under some conditions, a low permeability zone is createdwithin the formation in the vicinity of the borehole from invasion bythe drilling mud. In addition, if the mud filter cake is not removedcompletely when drilling has been completed, it forms a barrier to theflow of fluid into or out from the formation. The invention disclosedand claimed herein will shrink the hydrated, swollen clay in theformation, mud cake, and/or invaded zone so as to substantially increasethe permeability and mechanical and chemical stability of the formation.

Among the clays which may be present originally in natural geologicalformations or mayhave been introduced therein and which can beeffectively treated in accordance with the present invention there areincluded clay minerals of the montmorillonite group such asmontmorillonite, saponite, nontronite, hectorite, and sauconite; thekaolin group such as kaolinite, nacrite, dickite, and halloysite; thehydrous-mica group such as hydrobiotite, glauconite, illite andbramallite; the chlorite group such as chlorite and chamosite; clayminerals not belonging to the above groups such as vermiculite,attapulgite, and sepiolite; and mixed-layer varieties of the aboveminerals and groups. The clay content of the formations can be comprisedsubstantially of a single species of clay mineral, or of severalspecies, including the mixed-layer types of clay. Of the clay mineralscommonly encountered in the drilling of wells in natural geologicalformations which can be productive of the difiiculties herein noted andwhich can be treated etfectively in accordance with the presentinvention are clay minerals selected from the class consisting of themontmorillonite group, hydrous-mica group, chlorite group, and kaolingroup. It will be understood that the clay formations treated inaccordance with the invention need not be composed entirely of clay butmay contain other mineral components associated therewith.

Clays can swell and/ or disperse, disintegrate or otherwise becomedisrupted in the presence of aqueous fluids. A clay which swells is, notlimited to expanding latticetype clays but includes all those clayswhich can increase in bulk volume with or without dispersing,disintegrating or otherwise becoming disrupted when subjected to contactwith aqueous solutions such as water} certain brines, etc. Certain clayscan also disperse, disintegrate or otherwise become disrupted withoutswelling in the presence of aqueous solutions such as water, certainbrines, emulsions containing water or certain brines, etc. Some clays inthe presence of such aqueous solutions will expand and be disrupted tothe extent that they will become unconsolidated and move into aborehole. Formations which consist tremely large surface area comparedto that of an equivalent quantity of a granular material such as sand.This combination of small size and great surface area results in a highsurface energy with attendant unusual surface properties and extremeafiinity for surface-active agents. The structure of some of theseclays, as for instance montmorillonite, can be pictured as a stack ofsheet-like three-layer lattice units which are weakly bonded to eachother and which are expanded in the c crystallographic direction bywater or other substances which can penetrate between the sheets andseparate them.

All clay minerals have ion-exchange properties. Thus, for example,montmorillonite has a cation-exchange capacity of from about 90 to 130.milliequivalents per 100 grams of pure clay, illite from about 20 to 40milliequivalents, and kaolinite from about 5 to, milliequivalents.

Under ordinary oil-well conditions the ion-exchange reactions betweenthe clays and substances associated with the clays and capable. ofreacting therewith are essentially reversible. V

The properties of the clays vary widely with the cations occupying thebase-exchange positions or sites. A baseexchangc position or site can bedefined as an area, in this instance on a clay crystal, which hasassociated with it an exchangeable cation. Among the cations which aregenerally found on the base-exchange position or site can be mentionedsodium, potassium, calcium, magnesium, iron, hydrogen, etc. Thesecations are believed to be held to the clay surface by ionic forces.

The cations occupying the base-exchange sites on the clay can be thoseoriginally present or cations finding their way to the base-exchangeposition from the liquids in contact therewith. -Accordingly, the natureand concentrations of ions in the water in contact with the clay candetermine the cations occupying the base-exchange sites. In most oilWell formations, the natural waters associated therewith contain sodiumas the predominant cation, with calcium, magnesium and other cationspresent in much smaller quantities. Since the base-exchange positions onthe clay are occupied by cations, in many cases the cation will besodium when natural ground waters such as those described above areassociated therewith. Unfortunately, however, as for example in the caseof the sodium form of montmorillonite, these clay minerals swell in thepresence of water or certain brines and can, in some in stances, exertpressures up to thousands of pounds per square inch. Thus, dependentupon the amount of water absorbed, the clay can change to a rigid pasteor a gelatinous mass, or if sufiicient water is present, the clay candisperse completely into the aqueous phase.

We have found that the difiiculties noted above can be substantiallyreduced and a clay body can be stabilized to impart or maintainsatisfactory permeability to fluids, improved mechanical strength andincreased resistance to chemical attack by treating such clay body withdivalent substituted ammonium ions derived from p-phenylenediamine andsubstituted p-phenylenediamines represented by the following generalformula:

Y x-ii-X wherein X is selected from the class consisting of alkyl groupshaving from one to 3 carbon atoms; Y is selected 4 from the classconsisting of hydrogen and alkyl groups having from one to 3 carbonatoms, with the total number of carbon atoms in X+X+ Y being at least 2and no more than 8; Z is selected from the class consisting of hydrogenand alkyl groups having from one to 3 carbon atoms,

, with the total number of carbon atoms in being at least 3 and no morethan 14, and A is an anion such as chloride, bromide; iodide, nitrate,lactate, citrate, salicylate, formate, acetate, propionate, etc. Whilethe substituted ammonium ions defined above are effective claystabilizing-agents, the parent basicnitrogen compounds from which thesubstituted ammonium ions are derived have essentially noclay-stabilizing action.

The substituted ammonium ions can be obtained, among other ways, fromsalts prepared by reacting an appropriate basic nitrogen compound of theclass described with an acid, preferably one Whose anionic componentwill not form a precipitate with ions associated with substances such asaqueous fluids with which the substituted ammonium salt may come incontact. Thus, if the fluids contain a significant concentration ofalkaline earth ions, it is inadvisable to employ salts whose anioniccomponent may be sulfate, oxalate, ctc., since a precipitate can result.Among the compounds which can be employed in preparing the salts arehydrochloric acid, by drobromic acid, nitric acid, lactic acid, citricacid, salicylic acid, etc., lower fatty acids such as formic, acetic,propionic, etc., and methyl bromide, ethyl bromide, iso propyl iodide,etc. Among the salts which are satisfactory for use in accordance withthe present invention are p-phenylenediamine dihydrochloride,p-phenylenediamine dihydrobrornide, p-p henylenediamine dihydroiodide,pphenylencdiamine diacetate, pphenylenediamine disalicylate,p-phenylenediamine dicitrate, p-phenylcnediamine diformate,N,N-diethyl-p-phenylenediamine dihydrochloride,N,N-diethyl-p-phenylenediamine dihydrobromide, N,N-diethyl-pphenylenediamine dinitrate, N,N,N,N'-tetramethylp-phenylenediaminedihydrochloride, N,N,N',N-tetrarnethyl-p-phenylenediaminedihydrobromide, and N,N,N',N'-tetramethyl-p-phenylene diamine dilactate.

In treating the clay, substituted ammonium ions or mixtures of thesubstituted ammonium ions dissolved in any suitable polar solvent suchas water, methyl alcohol, ethyl alcohol, mixed solvents, etc. can beemployed. The solution employed can be of any desired concentration,from as little as one-hundredth molar to a saturated solution, butpreferably in a concentration of about 0.75 to about one and one-halfmolar.-

The amount of solution necessary to treat the clay body and obtain thebeneficial results of this invention depends on a number of variables,for example the amount of clay, the concentration of the treatingsolution, the porosity of the clay body, the desired depth ofpenetration into the clay body and the type of clay to be treated. Ingeneral, the clay is contacted with solutions of substituted ammoniumions in such amounts as to provide at least 1, and preferably at least5, milliequivalents of substituted ammonium ions per milliequivalent ofbaseexchange capacity of the clay. In any case, best results areobtained by using an excess of substituted ammonium ions, measured asmilliequivalents, over the number of base-exchange positions, alsomeasured as milliequivalents, on the clay to be treated.

To treat the clay with the solution containing the sub; stitutedammonium ions any suitable method that will assure effective contactbetween the solution and the clay can be employed. In treating aformation adjacent a well, for' example, the solution containing thesubstituted ammonium ions can be spotted adjacent the formation orformations to be treated and then be permitted to permeate theformation, pressure beingused to force the solution into the formationif desired. In addition, the

solution can be usedto treat an oil well formation by spotting, prior toshooting, a suflicient amount of the solution in a well bore adjacent asection to be shot and then shooting. Also, in gun perforating or jetperforating a well, the solution can be spotted through the interval tobe perforated and the gun then inserted and fired in the hole oppositethe interval. In secondary recovery, such as a water flood program, thetreating solution can be used in front of the flood to stabilize theclay in the formation as the flood progresses through the formation,thus precluding a drop in injection rate caused by reduced permeabilitydue to swelling and/or dispersing of the clay, In treating the formationadjacent a borehole of a well. which is producing hydrocarbons, thebeneficial results of this invention can be obtained by treating theformation with sufficient of the treating fluid to obtain a penetrationof at least one foot and preferably between occupying the base-exchangesites on the clay structure.

As aresultof this treatment, hydrated, swollen clay will shrinkessentially irreversibly, unhydrated clay will be rendered insensitiveto water and other swelling agents, and'the resistance of the clay tomechanical and chemical attack will be increased.

In order to demonstrate the eifectiveness of the substituted ammoniumions identified above as clay-stabilizing agents, we have run a seriesof tests in which various substituted ammonium ions were employed. Thesubsti- "tuted ammonium ions were formed by dissolving in water saltsobtained by the reaction of the basic aromatic nitrogen compound withhydrochloric acid. I Montmorillonite was chosen as the clay for thesetests because of its very high ability to swell and disperse. The testscomprised "placing 0.077 gram of montmorillonite (0.077 milliequivalentbase-exchange capacity) suspended in 5.0 milliliters of a salt solutionin a test tube. One liter of the salt solution prior to suspendingmontmorillonite therein contained 2,317 milligrams of sodiumbicarbonate,

279.9 milligrams of calcium chloride hydrate, 434.2 milligrams ofmagnesium chloride hydrate, and 0.86 milligram of magnesium sulfate. Thecontents of the test tube were allowed to set for 48 hours, after whichthe amount ofprecipitate was measured. The substituted ammonium ion wasthen added to the contents of the test tube in an amount equal to fivctimes the base-exchange capacity of the clay and the mixture was shakenfor minutes and subsequently allowed to stand for 24 hours. At the endof this period the volume of clay precipitate was estimated and suchquantity of supernatant liquid was withdrawn from the test tube that thevolume of the liquid and clay remaining was the same as the volume ofthe clay suspension originally treated. Fifteen milliliters of distilledwater were added to the resulting mixture and the test tube was shakenfor 15 minutes and allowed to stand for 24 hours, after which the volumeof clay precipitate was again estimated. This cycle was repeated anumber of times. At about the 15th test cycle and for one cycle only, asalt solution similar to that in which themontrnorillonite was initiallydispersed was substituted for the distilled water. Otherwise, theprocedure was not changed. Each cycle results in a decrease slaw saltconcentration of the aqueous solution and the concentration of treatingagent in equilibrium with the clay precipitate. This dilution processwill cause swelling and/ or dispersion of the clay if it has not beeneffectively stabilized. The substitution of the original .salt-solutionfor the distilled water at about the 15th Table I Compound Cycles toCycles to Colloidal Swelling Appearand/or.

ance Dispersion p-phenlenediamine dlhydrochlorlde N ,N diethyl pphenylenediamine dihydrochloride N ,N ,N ,N-tetramethyl-p-phenylenedlamine 1 dihydrochloride m-phenylenediaminedihydroehloride 4 a N-methyl-p-phenylenediamine dihydroehl ride 16 212,4-diaminotoluene dihydrochloride" 17 a 2,5-diaminotolueuedihydrochloride 19 a BA-diaminotoluene dihydrochloride. 5 a2,4,6-triaminotoluene trihydrochloride 7 a N-plhenyl-p-phenylenediami.ue dlhydrochlo- 2 rl e a N,N dlmethyl p phenylenedlaminemonohydrochloride 2 a N ,N-dimethyl-p-phenylenediamine dihydrochloride20 a denotes that the test was discontinued at the end of 24 cycles andno swelling, dispersion, or colloidal appearance was noted.

(9.) denotes that the test had a colloidal appearance at the cycleindieated in column "A but had not swelled or dispersed at the end of24eycles.

In the above table, by colloidal appearance it is meant that afterstanding 24 hours the supernatant liquid retains a turbid or opalescentappearance characteristic of that caused by the scattering of incidentlight by suspended colloidal particles. The appearance of such acolloidal condition indicates that the clay has not been stabilized bythe substituted ammonium ion tested. By swelling it is meant that thesettled volume of the clay at the end of 24 hours is at least 1 /2 timesthe settled volume of the clay at the beginning of the test. Bydispersion it is meant that the clay is dispersed uniformly throughoutthe liquid so that at the end of 24 hours no precipitate or sediment canbe detected. Obviously, when the clay swells or disperses it has notbeen stabilized by the particular substituted ammonium ion tested.

The above table graphically illustrates the advantages of the presentinvention. Thus, it can be seen that many substituted ammonium ionsderived from aromatic compounds related to p-phenylenediaminae. g.,N-methylp-phenylenediamine dihydrochloride, 2,4,6-triaminotoluenetrihydrochloride, 3,4-diaminotoluene dihydrochloride,2,5-diarninotoluene dihydrochloride, 2,4-diaminotoluene dihydrochloride,m-phenylenediamine dihydrochloride, N- phenyl-p-phenylenediaminedihydrochloride, N,N-dimethyl-p-phenylenediamine monohydrochloride, andN,N-dimethyl-p-phenylenediamine dihydrochloride, are unsatisfactory astreating agents for stabilizing clays, for clays treated therewith wereeasily dispersed and resulted in aqueous solutions having a colloidalappearance. Divalent substituted ammonium ions derived fromp-phenylenediamine and substituted p-phenylenediamines embraced by thegeneric structural formula defined hereinabove, e. g.,p-phenylenediamine dihydrochloride, N,N-diethylp-phenylenediaminedihydrochloride and N,N,NQN tetramethyl-p-phenylenediamiuedihydrochloride, proved to be very eifective, for evenat the end of 24cycles the clay treated therewith was unaifected by water or the saltsolution.

There follow illustrative embodiments of the actual practice of theprocess of this invention as applied to oil Wells producing fromformations containing clay. It is understood that the proceduresdescribed are illustrative and the invention is not to be limitedthereby.

p In treating a formation adjacent the bottom of a borehole to stabilizethe clay, said formation containing about percent by weight ofmontmorillonite and having a porosity of about percent, so as to attaina radial depth of treatment of at least 5 feet from the borehole, about150 gallons of a one-molar aqueous solution of substituted ammonium ionsderived from p-phenylenediamine dihydrochloride for each foot ofvertical thickness of the formation to be treatedis used. Whiletheoretically only about 70 gallons of the above treating solution wouldbe needed to react with all of the clay in the above volume offormation, an excess over the theoretical quantity is employed to assurerapid and complete reaction with the clay. The treating solution isintroduced through a string of small diameter pipe lowered to within afew feet of the bottom of the hole and allowed to flow in by gravity.Since the treating solution has a much higher specific gravity thanWater, oil or ordinary oil field brines, it will displace water or oilopposite the formation to be treated and will then flow into theformation. As an aid in displacing the treating 'solution into theformation, pressure can be employed. The treating solution is introducedinto the formation slowly and allowed to remain in contact with theformation for about 24 hours, after which the unused portion, along withproduced fluid, is withdrawn from the Well. It will be understood that,instead of treating formations adjacent the bottom of a borehole, anyselected formation interval above the bottom of the borehole can betreated in accordance with the invention by setting a bridge plug, inknown manner, at the bottom of the formation to be treated, andthereafter proceeding as described above considering the top of thebridge plug to be the bottom of the borehole.

The process of this invention is also used to advantage in secondaryrecovery operations wherein a displacement fluid such as water isapplied under pressure to an oilbearing formation by means of speciallyequipped input wells penetrating said formation for the purpose offorcing the oil out of the oil-bearing formation through an output wellpenetrating said formation. Such operations are often developed in whatis termed a five-spotpattern, with the producing well located in thecenter of a square formed by water'input wells at the four corners. Byintroducing any of the treating solutions disclosed herein into thewater input wells prior to injection of water, the treating solutionwill move ahead of the advancing water and thus stabilize the clay inthe formation before the clay has had an opportunity to come in contactwith the injection water and be deleteriously affected by contacttherewith. In actual practice, the treating solution is placed adjacentthe formation to be treated by introducing the same through a string ofsmall diameter pipe lowered to a point adjacent the section of theformation to be treated in the manner described in the paragraph nextpreceding and is followed by normal injection of water. To establish afront of the treating solution about five feet thick (radially) ahead ofthe injection water at a radius of about feet from the borehole in aformation having the same montmorillonite content and porosity describedabove,about 650 gallons of a one-molar aqueous solution ofp-phenylenediamine dihydrochloride is sufficient for each foot ofthickness (vertical) of the formation to be treated. Because of priortreatment in accordance with the invention, a satisfactory permeabilityof the clay during the water flood is maintained or improved, therebyleading to more efficient recovery of the fluids to be produced.

The treating solutions herein disclosed are also employed with advantagein oil-well perforating. When claywater drilling funds are used inrotary drilling, they seal off the openings in porous formationsencountered while drilling. In well completions Where such formationsare cased ofi. andthe casing must be perforated for production, thesealingproperty of clay-water muds can be detrimental. Since thehydrostatic head of the mud in the borehole exceeds the formationpressure, when the casing is perforated the clay-water mud rushes intothe perforated formation until a mud cake seal is established or thepressure is balanced. This often is accompanied by a fresh water loss tothe formation, which in the clay formations described, swells the claywhich is present. In addition, there often results blocking of theperforated formation to such an extent that on subsequent completion ofthe Well the perforations have to be washed or acidized with reagentsknown as mud clean out agents.

To avoid such difficulties in perforating operations in accordance withthe present invention, a string of tubing is lowered into the boreholeso that its lower end is adjacent the bottom of the section to betreated and about 300 gallons of a suitable oil-base drilling fluid isintroduced through the tubing to displace the clay-water drilling mudupwardly in the borehole. About gallons of a onemolar aqueous solutionof the treating solution, e. g., p-phenylenediamine dihydrochloride, foreach foot of thickness of the formation is thereafter introduced throughthe tubing and in turn displaces the oil-base drilling fluid upwardly inthe borehole. The perforating gun, either bullet or jet, is then loweredinto the treating solution opposite the formation to be treated and thecasing perforated in the usual manner. The hydrostatic head in theborehole exceeds the formation pressure and thus will force the treatingsolution into the formation. In this way, the naturally-occurring clay,which was exposed to fresh Water lost to the formation from theclay-water drilling fluid, will be shrunken and stabilized and When thewell is permitted to flow, or is swabbed or pumped, the unusedclay-stabilizing agent in the treating solution will be produced fromthe formation. This operation will leave the formation substantiallyfree from plugging by mud cake or other hydrated clay. Thus, byemploying any one of the treating agents disclosed herein whileperforating, the formation will be prevented from being mudded off, theharmful effects of fresh water on naturallyoc'curring clay will benullified, the necessity for washing perforations with so-called mudacids will be eliminated, and the use of conventional clay-waterdrilling muds will be permitted in areas where the producing formationscontain swelling-type clays and the more expensive oil-base muds arecommonly used.

Similarly in oil well shooting in open hole with high explosives, suchas nitroglycerine, trinitrotoluene, etc., the freshly exposed formationmay also be contacted with a clay-water drilling fluid with theaccompanying harmful effects described above. The drilling fluidopposite the formation to be treated in such case can be replaced withan oil-base drilling fluid followed by the treating solution in themanner described above, and the explosive can be lowered into thesolution and detonated in the customary manner. The beneficial resultsobtained in employing the treating solutions of the invention whileperforating will also accompany their use with high explosives.

While we have found that the specific substituted ammonium ionsdisclosed herein or mixtures thereof are satisfactory for the purposesof this invention, there are certain instances wherein it isadvantageous to employ in admixture therewith other substituted ammoniumions not specifically disclosed herein but which have similar propertiesthereto, as for example, the substituted ammonium ions disclosed in ourcopending applications filed concurrently herewith, application SerialNos. 469,855, 469,856 and 469,858 to 469,861, inclusive, as Well as inthe other concurrently filed copending applications in the name ofWilliam E. Brown, application Serial Nos. 469,854 and 469,862. Forexample, although by far the greatest portion of the base-exchange siteson a clay mineral surface will have an area approximating the averagearea per exchange site, a small number of sites will have warmconsiderably less than the average. Because of the spatial configurationof their hydro- 'p-phenylenediamine phobic part, certain substitutedammonium ions "will not be able to occupy these smaller sites, in whichcase it is advantageous to use one or more additional substitutedammonium ions of dilferent spatial configuration which can occupy theremaining positions and thus complete the stabilization reaction. ,It isbelieved that this use is especially advantageous in the case of themixed-layer clay minerals.

Obviously, many modifications and variations of the invention, ashereinabove set forth, may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare iridicated in the appended claims. I

We claim: 1. A method of stabilizing a clay-containing body whichcomprises contacting such clay-containing body with divalent substitutedammonium ions derived-from and substituted p-phenylenediaminesrepresented by the following general formula:

Y X-IiT-X HC/ (fiH 2A F Hb on o all-Z wherein X 18 selected from theclass consisting of alkyl groups having from one to 3 carbon atoms; Y isselected from the class consisting of hydrogen and alkyl groups havingfrom one to 3 carbon atoms, with the'total number of carbon atoms in X+X -|-Y being at least 2 and no more than 8; Z is selected from theclass consisting of hydrogen and alkyl groups having from one to 3carbon atoms, with the total number of carbon atoms in X +X Y+Z+Z+Zbeing at least 3 and no more than 14, and A is an anion. 40

2. A method of stabilizing a clay-containing body as in claim 1 in whichthe clay-containing body comprises at least one clay mineral selectedfrom the class consist ing of the montmorillonite group, hydrousmicagroup, chlorite group, and kaolin group.

3. A method of stabilizing a clay-containing body which comprisescontacting such clay-containing body with substituted ammonium ionsderived from p-phenylenediamine.

4. A method of stabilizing a clay-containing body which comprisescontacting such clay-containing body with substituted ammonium ionsderived from N,N-diethyl-p-phenylenediamine.

5. A method of stabilizing a clay-containing body which comprisescontacting such clay-containing body with substituted ammonium ionsderived from N,N,N,N'- tetramethyl-p-phenylenediamine.

6. A method of stabilizing a clay-containing formation adjacent a wellbore which comprises contacting such clay-containing formation withdivalent substituted ammonium ions derived fromp-phenylenediamine andsubstituted p-phenylenediamines represented by the following generalformula:

wherein X is selected from the class consisting of alkyl groups havingfrom one to 3 carbon atoms; Y is selected from the class consisting ofhydrogen and alkylgroups' having from one to 3 carbon atoms, with thetotal number of carbon atoms in X -{-X +Y being atleast 2 and no morethan 8; Z is selected from the class consisting of hydrogen and alkyl.groups having from oneto 3 carbon atoms, with the total number of carbonatoms in X+X+Y+Z+Z+Z being. at least 3 and no more than 14, and A is ananion. I

7. A method of stabilizing a clay-containing formation adjacent a wellbore which comprises contacting such claycontaining formation withsubstituted ammonium ions derived from p-phenylenediamine. 1

8. A method of stabilizing a clay-containing formation adjacent a wellbore which comprises contacting such claycontaining formation withsubstituted ammonium ions derived from N,N-diethyl-p-phenylenediamine.

9. A method of stabilizing a clay-containing formation 7 adjacent a wellbore which comprises contacting such I clay-containing formation withsubstituted ammonium ions derived fromN,N,N,N-tetramethyl-p-phenylenediamine..

10. A method of recovering oil from an oil-bearing: formation containingclay, wherein a displacement fluid under pressure is applied to saidformation through at:

least one input well penetrating said formation, and where-- in oil isrecovered from an output well penetrating saidv formation, whichcomprises introducing a treating solution containing divalentsubstituted ammonium ions de' rived from p-phenylenediarnine andsubstituted pphenyl- ."enediamines represented by the following generalformula:

wherein X is selected from the class consisting of alkyl groups havingfrom one to 3 carbon atoms; Y is selected from the class consisting ofhydrogen and alkyl groups having from one to 3 carbon atoms, with thetotal number of carbon atoms in X+X+Y being at least 2 and y no morethan 8; Z is selected from the class consisting input we'll, forcingsaid treating solution through said formation'by means of saiddisplacement fluid, and recovering oil from said output 'well.

11. A method of recovering ,oil from an oil-bearing formationcontainingclay wherein a displacement fluid under pressure is applied tosaid formation through at.

least one input Well penetrating said formation, and where in oil .isrecovered from an output well penetrating said formation, whichcomprises introducing a treating solution containing divalentsubstituted ammonium ions derived from p-phenylenediamine into saidinput well, thereafter introducing said displacement fluid underpressure into saidinput well, forcing said treating solution throughsaid formation by means of said displacement fluid, and recovering oilfrom said output well.

12. A method of recovering oil from an oil-bearing formation containingclay, wherein a displacement fluid under pressure is applied to saidformation through at least one input well penetrating said formation,and wherein oil is recovered from an output well penetrating saidformation, whichcomprises introducing a treating solution containingdivalent substituted ammonium ions derived from N,N-diethyl-p-phenylenediamine into said input well, thererecovering oilfrom said output well. v

11 after introducing said'displacement fluid under pressure into saidinput well, forcing said treating solution throngh said formation bymeensbf said-displacementfluid,

13. A method of recovering oil from an oil-bearing formation containingclay, wherein a displacement fluid underpressure is applied to saidformation through, at

least one input well penetrating said'formation, and wherein oil is,recovered from an output Well penetrating said I formation, whichcomprises introducing a treating solu tion containing divalentsubstituted ammonium ions I rived fromN,N,N',N'-tetramethyl-p-phenylencdiamine in to said input well,thereafter introducing said displacemcntfluid under pressure into saidinput well, forcing said treating solution through said formation bymeans of said displacement fluid, and recovering oil from said outputwell.

B tween @191 the l 9 this Patent

1. A METHOD OF STABLIZING A CLAY-CONTAINING BODY WHICH COMPRISESCONTACTING SUCH CLAY-CONTAINING BODY WITH DIVALENT SUBSTITUTED AMMONIUMIONS DERIVED FROM P-PHENYLENEDIAMINE AND SUBSTITUTED P-PHENYLENEDIAMINESREPRESENTED BY THE FOLLOWING GENERAL FORMULA: